Strong high pressure baked much of the West in high heat Wednesday, and forecasters said the siege would last into the Labor Day weekend and likely beyond.

A crazy-quilt of excessive-heat warnings, watches and advisories along with Red Flag warnings of high fire danger and air quality alerts due to smoke from wildfires blanketed the region from Southern California to Washington state and as far east as Montana.

In northwestern Nevada, where thousands of people have gathered in the desolate Black Rock Desert for the annual Burning Man festival, temperatures are expected to top 100 degrees during the weekend.

“A lot more will be burning than just the wooden figure,” Mark Deutschendorf, a meteorologist with the National Weather Service office in Reno, told the San Francisco Chronicle.

A weak low-pressure system brought some cooling to Washington and onshore flow created temporary relief from smoky conditions, but forecasters said the heat would return Friday.

In California, record-breaking inland temperatures backed off just a notch Wednesday as utility crews worked to restore power to thousands after extreme heat Tuesday caused electrical distribution equipment to fail.

Utilities continued to ask customers to reduce power usage, and the Los Angeles County health officer extended a heat emergency declaration through Sunday in valleys north and east of downtown, warning that “extreme measures” should be taken to protect vulnerable people such as older adults, infants and children.

“Confidence is pretty high that area temperatures will remain above normal through next week,” the Los Angeles-area National Weather Service office wrote. “The question is will it be extremely hot or just hot?”

Los Angeles Department of Water and Power crews worked to restore power to thousands of customers after high-voltage equipment at two distributing stations overloaded Tuesday afternoon. Workers were rerouting circuits to others that were less overloaded and installing portable equipment where rerouting was not possible. The utility said it dealt with a high volume of other power outages Wednesday.

The operators of the California power grid did not repeat Tuesday’s call for voluntary statewide reduction in power use, but the Los Angeles utility asked its 1.4 million customers to continue cutting back, and Pacific Gas & Electric and San Diego Gas & Electric activated incentive programs that called for certain customers to reduce use of power during a four-hour period Wednesday afternoon.

Flood advisories were issued for some interior areas of Southern California deserts and mountains, including a large area of Death Valley National Park, as thunderstorms unleashed heavy rains.

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